PbO2 Research Articles

Electrocatalysis coupled super-stable mineralization for the efficient treatment of phosphorus containing plating wastewater

The automotive, electronics, and aerospace sectors use electroless nickel plating (ENP) technology for surface treatment. Hypophosphite, a widely used reducing agent in ENP, generates large volumes of hypophosphate (H2PO2-) and nickel ions (Ni2+) in its wastewater which poses potential risks to human health. However, it is a highly challenging task to remove and recycle the H2PO2- and Ni2+ from such wastewater. In this study, a novel electrocatalysis coupled super-stable mineralization process was developed for the treatment of phosphorus-containing ENP wastewater. The electrocatalytic system, utilizing commercial lead dioxide and stainless steel as the anode and cathode, separately, achieved remarkable results in simultaneously removing H2PO2- and recycling valuable Ni2+ ions from ENP wastewater, with a 99.1 % oxidation efficiency for H2PO2- and a high recovery rate of 99.8 % for nickel. In order to meet industrial emission standards, layered double hydroxide (CaAl-LDH) and its calcined derivatives (CaAl-900) were employed as super-stable mineralizers for the further treatment of total phosphorus (TP) and residual Ni2+ in the wastewater. The mechanism underlying the enhanced treatment of ENP wastewater was elucidated through free radical quenching experiments, revealed superoxide radicals (·O2–) as the primary active species. It is noteworthy that the successful treatment of actual ENP wastewater was achieved, meeting standard discharge requirements. This study provides novel insights for achieving resource-efficient wastewater treatment and promoting environmentally friendly electroplating industries.

Zirconium-doped lead dioxide anodes prepared by sol-gel method for ampicillin removal from simulated pharmaceutical polluted wastewater.

New anodes consisting of zirconium-doped PbO2 coating, growth on titanium dioxide interlayer, were deposited on titanium substrates using spin coating method and have been tested for the removal of ampicillin, a β-lactam antibiotic, from water. Morphological, structural, and electrochemical properties of the prepared coatings were characterized by scanning electron microscopy (SEM), atomic force microscope (AFM), X-ray diffraction (XRD), and electrochemical impendence spectroscopy (EIS). Results showed that the incorporation of zirconium dopant had a noticeable modification in the morphology of anodes. An increase in the surface roughness and the specific active area were observed with Ti/TiO2/PbO2- 10% Zr electrode compared to other anodes. The electrochemical measurements indicated that the anode doped with 10% Zr showed a more protective coating performance than the undoped and 20% Zr-doped PbO2 electrodes. The experiments on ampicillin degradation revealed that doped lead dioxide anodes have excellent electrocatalytic activity. The major byproduct generated during anodic oxidation treatment has been identified as ampicilloic acid by liquid chromatography-mass spectroscopy (LC-MS) analysis. Results demonstrated that Ti/TiO2/PbO2- 10% Zr anode presents the best removal rate of ampicillin with a minimum intermediate amount, which leads to conclude that 10% is the optimum percentage of zirconium dopant for antibiotic wastewater treatment.

Facile development of flexible cellulose acetate-lead dioxide membrane electrodes for supercapacitor applications

Current work focuses on the development of flexible membranes of cellulose acetate containing lead dioxide for supercapacitor applications. The functionality of cellulose acetate and lead dioxide are analyzed by Fourier transform infrared spectroscopy. The degree of crystallinity is studied using X-ray Diffraction. The degree of hydrophilicity is discussed by water contact angle measurements. A Universal Testing Machine is used to examine the mechanical properties. The electrochemical performances are illustrated using Cyclic voltammetry, Electrochemical impedance Spectroscopy and Galvanostatic charge-discharge techniques. The highest recorded specific capacitance is 148 F g−1 at a current density of 40 mA g−1 for a membrane of 1 wt% lead dioxide in cellulose acetate. Capacitance retention of 89% after 5000 cycles is attained. The power density of 56 W kg−1 and energy density of 10 Wh kg−1 is achieved. The cellulose acetate doped with lead dioxide membranes can provide a better electrode material matrix for flexible energy storage.

Effect of Tween 80 on the Electrocatalytic Performance of a Ti/PbO2‐MWCNTs Electrode

AbstractIn this work, Ti/PbO2‐MWCNTs anodes modified with different amount with different amount of Tween 80 (0.0–2.0 g/L) were prepared by the direct current electrodeposition method used as anode materials for Zinc electrowinning. The MWCNTs were dispersed in a lead nitrate solution with Tween 80, and the effects of the amount of added Tween 80 on the morphology, phase composition and electrocatalytical performance of lead dioxide coating were investigated. Physical characterizations show that with the increase of the amount of Tween 80, both grain size of PbO2 and carbon content in PbO2 layer firstly increased and then decreased, the preferential orientation and crystallinity of the PbO2 grain growth in the deposition process changed. Electrochemical tests demonstrate that the optimal modified electrode achieved the minimum Eo value and maximum j0 of 2.038 V and 3.781×10−4 A, respectively, an increase of capacitance to 368.8 μF cm−2, and a decrease of charge transfer resistance to 92.74 Ω cm2, which is mainly attributed to the PbO2 electrode modified with Tween 80, coupled with the synergistic effects of MWCNTs doping.

Fabrication of Ti/Zr-SnO2/PbO2-Nd Electrode for Efficient Electrocatalytic Degradation of Alizarine Yellow R

Introduction: A novel attempt to degrade alizarine yellow R (AYR) by lead dioxide (PbO2)/ neodymium (Nd) coated Ti anode was investigated. Method: Ti/Zr-SnO2/PbO2-Nd electrode showed high oxygen evolution potential, high current density, and neutral conditions, which favored the degradation of AYR. The PbO2-Nd layer on Ti/Zr-SnO2 was further characterized by scanning electron microscopy, and X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The electrochemical properties of Ti/Zr- SnO2/PbO2-Nd electrode were evaluated by cyclic voltammetry, AC impedance spectroscopy, and accelerated life test. Result: The relatively higher oxygen evolution overpotential (~1.80 V) of the developed electrode can effectively suppress the occurrence of surface side reactions and oxygen evolution. A relatively lower charge transfer resistance (Rct, 18.0 Ω) of Ti/Zr-SnO2/PbO2-Nd electrode could be found. The Ti/Zr-SnO2/PbO2-Nd electrode exhibited an accelerated lifetime of 110 min under a very high current density of 10,000 A/m2. The doping of Nd could produce loosely-stacked sheet-like structures, thus, the number of active sites on the electrode surface increases. Conclusion: Moreover, an outstanding conductivity of Ti/Zr-SnO2/PbO2-Nd electrode was obtained, which favored the electron transfer and catalytic activity of the modified electrode. The Ti/Zr-SnO2/PbO2-Nd electrode exhibited improved electrochemical performances and higher oxygen evolution potential, and the highest oxygen evolution potential is 1.80 V. Under the current density of 30 mA/cm2, the electrocatalytic degradation of 92.3% could be achieved in 180 min. The electrochemical oxidation of AYR at the Ti/Zr-SnO2/PbO2-Nd electrode proved to be feasible and effective, indicating that it might be used for the elimination of AYR from wastewater. conclusion: The electrochemical oxidation of AYR at the Ti/Zr-SnO2/PbO2-Nd electrode proved to be feasible and effective, indicating that it might be used for the elimination of AYR from wastewater.

Numerical analysis on the flow and heat transfer characteristics of heat exchanger with cruciform tube

The heat exchanger (HE) is widely used in energy and power industries, which has a vital impact on the stability and efficient operation of relevant industrial systems. Different shaped heat exchange tubes are often designed specially to improve the thermal–hydraulic efficiency of HEs. In the study, two new geometries named the cruciform twisted tube and cruciform straight tube are introduced, and the heat & mass transfer properties of liquid lead (Pb) and supercritical carbon dioxide (s-CO2) in the HEs are numerically studied to assess the thermal–hydraulic efficiency and application prospect of two kinds of cruciform tube HEs. The results demonstrate that the unique cross-section geometry of the cruciform tube improves the uniformity of the flow field, and the spiral structure of the cruciform twisted tube effectively improves the blending and turbulence of working fluid. The cruciform tube can improve the comprehensive performance of the HE by more than 12%.

Role of Side Reaction Involving PbOx in Soluble Lead Redox Flow Battery: Effect on Cyclability

Soluble lead redox flow battery (SLRFB) has been an active subject of investigation in the past two decades because of its high energy efficiency (~70%) and charge efficiency (~90%) [1]. During charging, Pb2+ ions deposit as solid lead dioxide (PbO2 ) on anode and solid lead (Pb) on cathode, respectively. These features permit a membrane-less single-compartment design, making SLRFB a cost-effective electrochemical energy storage device. Discharge occurs by electro-dissolution of these solids, regenerating the electrolyte. The limited cycle-life of SLRFB is its current deployment challenge (best achieved about 100 cycles [2]). The shedding of solid lead dioxide over cycling is an indirect irreversible loss of active material from the electrolyte, the reason for SLRFB’s limited cyclability.Mathematical models link the deposit formation and the two-step charging potential profile through a side reaction involving PbO and PbO2 [3-5]. Morphological changes in deposit during cycling have been reported and presented as an alternate justification to the two-step potential profile [6]. To clarify these, we tested the role and feasibility of re-oxidation of solid PbO on cycling under varied conditions using an in-house prepared Nafion membrane-divided cell. We show that the charging through side reaction does not occur without the availability of Pb2+ near the electrode. We also show that the observations are independent of the electrodes’ age, the amounts of PbO and PbO2 present, and the applied current density. We obtained FESEM images of anode after short re-charging in a single-compartment design. We observed the formation of a new phase, plausibly lead dioxide from Pb2+ ions, leaving the solid residue almost unaffected. These findings challenge the idea of charging sustained in part by the oxidation of PbO through the side reaction. The deposit, constituted by whisker-like particles (thickness~200 nm), appears weak and layered. Gas evolution reactions known to occur under the limited availability of Pb2+ ions may promote residue disintegration. These observations lead us to hypothesize that cycling leads to irrecoverable residue accumulation, which may negligibly participate in further re-oxidation through the side reaction. These cumulative effects, accompanied by formation of a new phase at every charging, appear to contribute significantly to restricting SLRFB to a short cycle-life. These features raise concerns about the prevailing hypotheses about SLRFB dynamics and suggest need for strict design and operational controls to avoid residue buildup.

A new protective glass material against gamma ray: Thorough analysis to determine the impact of adding gadolinium (III) oxide

This work presents a study of the effect of replacing lead dioxide and gadolinium (III) oxide with boron trioxide on the physical, mechanical, and radiation shielding properties for the B2O3-Na2O-ZnO-PbO2-Gd2O3 glass systems. The Archimedes method confirms that the increase in the PbO2+Gd2O3 concentration within the fabricated glass system in the range from 16 to 22 mol.% increases the fabricated glass samples' density from 4.052 to 4.408 g/cm3. Additionally, the Makishima-Mackenzie model was utilized to investigate the influence of PbO2+Gd2O3 on the mechanical properties of the investigated glass samples. The increase in the substituting of PbO2+Gd2O3 decreases the fabricated glass samples' mechanical properties and micro-hardness. Furthermore, the Monte Carlo simulation method was applied for the estimation of the impact of PbO2+Gd2O3 concentration on the fabricated samples' radiation shielding parameters. The increase in the concentration of PbO2+Gd2O3 with range of (16, 18, 20 and 22) leads to increase the linear attenuation coefficient (LAC) to 8.014–11.517 cm−1 at 0.06 MeV, 0.381–0.423 cm−1 at 0.6 MeV, 0.133–0.149 cm−1 at 5 MeV, and 0.132–0.154 cm−1 at 15 MeV with the same order, respectively. Therefore, the introduction of PbO2+Gd2O3 concentration enhances the fabricated glass samples' radiation shielding properties to be suitable for γ-ray shielding applications.

Correction: Anodic oxidation as promoting technology for treatment and reuse of industrial textile effluent using ruthenium-doped lead dioxide (PbO2) anode

Correction: Anodic oxidation as promoting technology for treatment and reuse of industrial textile effluent using ruthenium-doped lead dioxide (PbO2) anode

Photoelectrocatalysis degradation of P-aminophenol using PbO2-TiO2 heterojunction electrode: Catalytic, theoretical calculating and mechanism

To lengthen the lifetime and extend the potential commercial applications of lead dioxide electrode. Herein, PbO2–TiO2 heterostructured electrodes were fabricated via direct current electrodeposition and the surface of the electrode was characterized by electron microscopy (EDS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The PbO2–TiO2 heterostructure electrode could produce an obvious photocurrent under UV irradiation, indicating a photoelectrocatalytic reaction. The PbO2–TiO2 heterostructured electrode was examined using density functional theory calculations(DFT). Work function(WF) confirmed that the applied electric field is conducive to the movement of photoelectrons, which promotes the photoelectrocatalysis effect. The nudged elastic band(NEB) results showed that the PbO2–TiO2 heterostructure electrode can promote the formation of •OH by reducing the activation barrier. The PbO2–TiO2 electrode was used as an anode to treat P-aminophenol (PAP) wastewater simulated wastewater and real PAP wastewater via photoelectrocatalytic degradation. The PbO2–TiO2 electrode effectively removes chemical oxygen demand (COD) from actual wastewater was 54.93 %,The after-treated Pb2+ concentration (0.037 mg·L−1) was lower than China’s wastewater discharge standard (1 mg·L−1). Finally, the degradation pathway of PAP was determined based on the intermediates detected using gas chromatography–mass spectrometry and the reactive sites of PAP were predicted using the Fukui function.These results suggest that the photoelectrocatalysis degradation of PAP using electrodes is feasible.

Anodic oxidation as promoting technology for treatment and reuse of industrial textile effluent using ruthenium-doped lead dioxide (PbO2) anode

Anodic oxidation as promoting technology for treatment and reuse of industrial textile effluent using ruthenium-doped lead dioxide (PbO2) anode

The mechanism of Fleury test for morphine

The test under study is due to M. Fleury. He used morphine dissolved, at room temperature, in 1/20 N sulphuric acid; added some lead superoxide (lead dioxide), stirred for 8 min., let stand 4 min; the water-clear liquid was separated, and a drop of ammonia was added. A brown colour occurs immediately. These experimental data indicate not a fast reaction, but a rather complex mechanism. In this communication a reaction mechanism is provided for the first time. Protonated lead dioxide is the reactive species which on interaction with the phenol group in morphine forms a mixed ortho-plumbate. Protonation of this ester does not favor further reaction. However, reaction with a second reactive species is favourable for a push-pull seven-member reaction mechanism. Enolization of the dienone formed restores aromaticity. Protonation of the Pb=O double bond in the obtained intermediate promotes a 7-atom concerted mechanism. 2,3-Dioxomorphine is formed along with an oxide hydrate that yields water and two molecules of plumbous oxide.

Use of Zinc Coatings As Anode Materials in Electrochemical System with Perchloric Acid and Lead Dioxide for Fast-Activated Reserve Chemical Power Sources

Use of Zinc Coatings As Anode Materials in Electrochemical System with Perchloric Acid and Lead Dioxide for Fast-Activated Reserve Chemical Power Sources

Characterization of lead dioxide composite electrode and its electrochemical properties

TiO2 nanoparticles, as a typical inert metal oxide, were added into [Formula: see text] plating solutions to prepare Ti/PbO2+nano-TiO2 composite coatings. The effect of TiO2 nanoparticles on the electrodeposition process of PbO2 was investigated by voltammetric studies. The composition, structure and morphology of the obtained composite coatings were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM), respectively. Cyclic voltammetry was employed to study the effect of nano-TiO2 particles on the PbO2 electrodeposition process. It is found that high doping (2–8 g/L) of TiO2 nanoparticles significantly decreased the crystallite size which can be attributed to a crystallite-refining effect of nano-TiO2 during the electrodeposition of PbO2.

Controlled synthesis of quasi-single-crystal lead dioxide by polyvinylpyrrolidone for enhanced electrochemical ozone production

The crystal facet of PbO2 has been proved to be a key factor affecting its electrochemical ozone production (EOP) performance. However, PbO2 with smooth and uniform crystal surface and single-crystal nature, which is the basis and prerequisite for PbO2 crystal facet engineering, has not yet been reported. In this study, by adding polyvinylpyrrolidone (PVP) as a facet modifier during the hydrothermal synthesis, a quasi-single-crystal PbO2 (PVP:Pb(CH3COO)2·3H2O=48:100, PVP-48) with (110) and (101) exposed facets was successfully synthesized. Compared with commercial PbO2 prepared by electrochemical deposition, PVP-48 exhibits excellent electrochemical catalytic activity due to its special crystal structure, and achieves the highest current efficiency of 11.9 % at a current density of 0.83 A/cm2. Further calculations show that PVP prefers to adsorb onto the (110) facet of the lead dioxide and reduces its surface energy, thereby exposing the (110) facet more readily. This work demonstrates the importance of PbO2 facets composition and provides new ideas for further controllable synthesis of PbO2 with specific facet structure and higher EOP efficiency.

Effect of bismuth doping on electrodeposition, physicochemical properties and electrocatalytic activity of lead dioxide electrodes

The bismuth (Bi)-doped PbO2 electrodes were electrodeposited from a nitric plating solution containing Pb (II) and Bi (III) ions by varying the concentrations of Bi (III). Cyclic voltammetry was used to investigate the effect of Bi (III) ions on the kinetics of PbO2 electrodeposition. It is observed that increasing Bi (III) ions in the plating solution reduces the rate of nucleation or formation of PbO2 but does not change the process mechanism. X-ray diffraction confirms that the incorporation of bismuth results in an apparent β (301) texture. Scanning electron microscopic observation reveals that the size of the PbO2-deposit particles gradually decreases by several micrometers as the doping content of Bi (III) increases from 2 to 6 mM. Linear scanning voltammograms show that the oxygen overpotential on Bi-PbO2 is much higher than on undoped PbO2 electrodes. Electrochemical degradation of the target pollutant was performed, and HPLC analysis demonstrated that Bi doping significantly improves the electrocatalytic ability of PbO2 electrodes.

Electrochemical Oxidation of Ethylene Glycol in Aqueous Media Using Lead Dioxide Titanium Anode

Experiments on the electrochemical oxidation of ethylene glycol (EG) have been carried out in laboratory conditions using lead dioxide titanium anode (LDOTA) in electrochemical cell. It has been found that the chemical oxygen consumption in the solution on LDOTA at a current density of 5.5 A/dm2 and processing time of 120 min is reduced to the values that allow its further bio-purification. It has been concluded that the efficiency of the electrochemical oxidation process, leading to further destruction of the EG molecule, is explained by both direct oxidation, in which the hydroxyl radicals arise that oxidize EG on the anode surface, and indirect oxidation, accompanied by the formation of strong oxidizing agents, for example, peroxodisulfuric acid anions capable of oxidizing the organic matter in the solution volume.

Fabrication and characterization of a novel multilayer heterojunction Si3N4-PbO2 nanocomposite electrode and its application on electrocatalysis degradation of sulfathiazole

To lengthen the lifetime and extend the potential commercial applications of lead dioxide electrode, herein, a novel multilayer heterojunction Ti/ SnO2-Sb2O3/ graphene oxide/ carbon nanotube/ Si3N4-PbO2 electrode (Si3N4-PbO2 electrode) was fabricated by co-electrodeposition process that doping Si3N4 nanoparticles in eletroplating solution. Various spectroscopic and microscopic techniques, including scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS), were employed to characterize the surface of the fabricated electrode. The EDS analysis confirmed the successful attachment of 5.49 %wt Si and 2.46 %wt N elements from Si3N4 nanoparticles onto the PbO2 surface, while the XRD results indicated a shift in the preferred orientation of PbO2 grains from β(110) to β(101). The water adsorption energy and ·OH desorption energy in the electrocatalysis process were determined to be 0.71 eV and 0.241 eV through theoretical calculating. Subsequently, the Si3N4-PbO2 electrode was employed as an anode for the electrocatalytic degradation of sulfathiazole-simulated wastewater and real sulfonamides wastewater. Under optimized conditions determined via response surface methodology (RSM), the COD degradation efficiency reached 69.37 % for sulfathiazole and 62.35 % for real sulfonamides wastewater. The final COD concentration of the real sulfonamides wastewater was reduced to 77.05 mg/L, under the national urban sewage discharge standard. Finally, the degradation mechanism and pathway of sulfathiazole has been arranged based on the electron spin resonance (ESR), cyclic voltammetry (CV), while the intermediates were detected by Gas Chromatography-Mass Spectrometer (GC-MS) and the reactive sites of sulfathiazole were predicted by using Fukui function.

Phosphoric Acid Activation of Titanium-Supported Lead Dioxide Electrodes for Bipolar Battery Applications

Titanium foil coated with doped tin dioxide is an attractive option for the positive current collector interface of bipolar lead batteries due its corrosion resistance and mechanical performance. The phosphoric acid and two of its derivatives, one inorganic (calcium hydrogen phosphate) and one organic (poly-vinylphosphonic acid), have been studied as additives with potential for improvement of the capacity retention of such positive electrodes. The results show that the jar-formation process of the electrodes in the sulfuric acid electrolyte containing phosphoric acid successfully overcomes the capacity retention problem at all studied cases. This leads also to considerable improvement of the lead dioxide utilization. The cycling ageing of the electrodes combined with periodic impedance spectroscopy measurements, indicate progressive capacity loss corresponding to the typical processes of degradation of the lead dioxide structure. Rather small changes in the electrode resistance prove the corrosion and the passivation resistance of the current collectors. It is concluded that the combined doping with phosphoric acid species in the electrolyte and in the positive paste offers a potential for further improvements of the electrodes cyclability.

Elastomeric impression materials used in modern orthopedic dentistry

This article presents a review of elastomeric impression materials currently used in orthopedic dentistry. The elastomer group is divided into silicone, polyester, and thiocol (polysulfide) materials. Silicone impression materials are widely used in orthopedic dentistry. Their structural basis is polymethylsiloxane with active terminal hydroxyl groups. Polyester materials consist of the main and catalyst components (pastes). The main component contains a polymer with imine groups, fillers, and plasticizers. Sulfonic acid ester is present in the catalyst paste. When these two components are mixed, ionic (cationic) polymerization occurs. Polysulfide materials are produced as base and catalyst pastes. The structural unit of the main paste is polysulfide or mercaptan rubber, and the catalyst paste acts as an oxidizer. Lead dioxide is often used as an oxidizer. The resulting polymer does not have a stereoregular structure, which causes its stickiness. It is technologically challenging to obtain a polymer with a stereoregular structure.
 When theoretically comparing the listed types of elastomeric impression materials, according to their properties, chemical composition, advantages, and disadvantages, polyester and polysulfide impression materials can be distinguished as more advanced. Silicone materials have disadvantages; however, they are often used for domestic dentistry owing to the presence of domestic manufacturers and relatively low cost.